This program project represents a highly coordinated and in-depth study of biological oxidation-reduction reactions and energy transduction with particular emphasis on mitochondrial oxidative phosphorylation. The individual investigators each have areas of interest and methodological expertise which complements those of the other investigators. Their combined talents will attack the problem in four interlocking parts: (1) A study of the chemical, physical and kinetic properties of the oxidation-reduction components of the respiratory chain, including interactions among these components; (2) A study of the orientations of the redox carriers with respect to the plane of the mitochondrial membrane and the distances between them; (3) A study of the mechanism for transducing the energy available in the oxidation-reduction reactions into a form suited to ATP synthesis and ion transport; (4) A study of the interactions of the oxidation-reduction components with the mitochondrial membrane and the role of the membrane in controlling the kinetic and thermodynamic properties of biological reactions. The objective is to gain a thorough understanding of the chemical events of oxidative phosphorylation in order to provide a basis for understanding its role in cellular metabolism.